1. Field of the Invention
The present invention generally relates to a method for monitoring paraben and, more particularly, to a method for monitoring level of paraben.
2. Description of the Related Art
With respect to FIG. 1, parabens, also named as para-hydroxybenzoic acid, are a class of chemicals including methyparaben (MP), ethylparaben (EP), propylparaben (PP), butylparaben (BP), isopropylparaben (IPP), isobutylparaben (IBP) and secbutylparaben (SBP). With bactericidal and fungicidal properties, parabens are widely used as preservative by cosmetic and pharmaceutical industries to prolong shelf life of cosmetics and medications. However, parabens are becoming increasingly controversial. As a xenoestrogen (XE) and an endocrine-disrupting compound (EDC, also called as environmental hormone), parabens pose estrogenic activity and may affect male reproductive system, thereby being harmful to human body. Moreover, for human body with irritable the physique, parabens may probably induce allergic reaction and photosensitivity. Therefore, it is necessary to highly monitor the level of paraben.
In a conventional method for monitoring level of paraben, first by a process named solid phase extraction, a membrane or a column is used to extract a sample. The resultant extract is further analyzed by reversed-phase high performance liquid chromatography (RP-HPLC) in combination with ultraviolet detector (UV) or diode array detector (DAD).
However, due to the process of solid phase extraction comprises separation and extraction, 0.2 to 20 g of the sample is needed in the conventional method for monitoring level of paraben. That is, the conventional method for monitoring level of paraben is not suitable for the samples, which are expensive or difficult to afford.
Furthermore, due to the RP-HPLC procedure, the conventional method for monitoring level of paraben requires a long analyzing time for one sample and an additional cleaning time for cleaning the column between one and another samples used in the RP-HPLC procedure. That's why the conventional method for monitoring level of paraben is time-cost and not suitable for large-scale screening.
Besides the cleaning time, a lot of organic solvents are also required to clean the column used in the RP-HPLC procedure. The resultant waste organic solvents are therefore becoming pollution to the environment. Thus, the conventional analysis of paraben may be harmful to the environment.
In light of this, it is necessary to improve the conventional method for monitoring level of paraben.